thake



A I. A. THAKE. RENEWABLE LINK ELECTRIC FUSE APPLICATION FILED MAY II,|918 Patented 006.121,1919.

Y akfoz natia' JOI-IN A. THAKE, F BROOKLYN, NEW YORK.

RENEWABLE-LINK ELECTRIC FUSE.

Specification of Letters Patent.

Patented' oet. a1, 191e Application iled May 17, 191`8l Serial No.235,150.

To all whom t may concern:

Bey it known that I, JOHN A. THAKE, a Citizen of the United States, anda resident of the borough of Brooklyn, in the city and y" State of NewYork, have invented certain new and useful Improvements in Renewable-Link Electric Fuses, of which the following isia specification.

gThis invention is intended, primarily, for

lo so-oalled plug fuses, in which the fusible link is mounted in a shellor capsule, with kone end of the link connected with a surroundingmetallic sleeve, threaded to adapt the plug to screw into and contactwith the conducting Wall of a socket, while the other end of the linkprotrudes axially from or is l.connected with a central terminal uponthe fplug, in position to contact with another terminal Within thesocket.

In United States Letters Patent No. 628,180,'issued in i899 to Johnston,it has heen proposed, in making plug fuses, to seat one end of a linkwire in. the eye of a pin inserted through the inner end of the shelland having a head to limit its insertion and provide an externalcontact, the outer end of the shell being provided with a closure thatis removable to admit of connecting up the other end of the link wirewith the surrounding metallic sleeve through the inedium of a rigid armprojecting therefrom.

The present invention follows this general plan of assembly, but employsa delinitely formed link that is integral with the limitingandcontacting head; and the inserted end of the fuse link is supported by aspring arm constructed with a seat that receives and grips a speciallyformed head on' the link, the position of the arm and length of 4o thelink being such that hanging the link in its seat on the arm enforcesconsiderable depression of the resilient arm and leaves the link and armunder considerable tension.

There are several advantages accruing from such an assembly of theparts. The link is integral with its central contact as required by theunderwriters. The tension prevents vibration and maintains a goodContact between the `inner end of the link and the spring arm andenforces quick separation of the parts of the link when fused. Another ydistinct and in'lportant function realized from the resiliency of thearm is that when the fuse acts, under an overload, the arm snaps outwardagainst or in such relation to the end-closure as to serve as anindicator or telltale, the disk of the end closure being preferablytransparent to facilitate observation. An important advantage arisingfrom the use of integral heads of special form upon links ofpredetermined length is that the heads enter the appropriately formedseats provided for them without the use of fastenings or manipulation ofthe material of the link; tensioning the spring arm and setting it as anindicator is assured; the heads can be labeled or marked to indicate thecapacity of the fuse link; and the intro duction of links ofinappropriate capacity is discouraged. Moreover, the capacity of thelink is always open to inspection, through its marking presented beneaththe transparent end closure or Window, and im proper use of links ofexcessive capacity would readily be detected. The conforming of the endopening of the shell and that portion of the fuse that seats therein notonly safeguards against introduction of an. iin..- proper link, hutprevents rotation of the lin'l-r in the seat when the shell is screwedinto the socket.

ln the accompanying drawing in which one ei'n'lJodiment of the inventionis shown by way of illustration:

Figure l is an axial section of the plug fuse intact, the position ofthe hanger after blowing being shown in dotted lines;

`Fig. 3 is a bottom plan view;

Fig. l is a section on the line 4 1 of Fig. l;

lfigs. and @are detail views of the link and the resilient support,respectively;

Fig. Z shows a modified construction of hanger.

A represents the body of the shell which is of usual construction, heingmade of porcelain or other non-conducting material, and formed withthreaded head a to receive the collar B for securing the transparent endclosure disk C; also with reduced outer wall a to receive the screwsleeve D, bore a2 to receive and position the resilient arm E thatengages the head f of link F and present the lower end of said arm forcontact with the screw sleeve; also an end opening i3 through which thelink enters and in which Jthe head f on the outer end of the link seats.

Spring arm E assumes an approximately radial position in the shell,extending inwardly from its tang e that enters the longitudinal bore t2and extends beneath the sleeve D, and said arm terminates in the seat cthat is slotted to admit the inner end of the link, and eoncaved toembrace the same head on said end and prevent the displacement of saidhead so long as the arm acts under its own elasticity.

Link F is of fixed length and has its heads f, f that enter the seats asand c made in tegral therewith; head f being small -enouo'h to passthrough the seat a3 in entering the shell, and hea-d being large enoughto limit the insertion, rest upon seat er and pr vide the centralcontact Head f is angular, and the opening of seat (t3 conforms thereto,so that the head cannot turn in its seat in screwing in the plug, and sothat other forms of link may not be readily introduced.

In assembling one of the new links with the shell, the end closure isremoved, the link is passed through the opening' of seat a3 untilarrested hy the link head f', the resilient arm E is depressed until thereduced portion of the link, beneath the inner head f, can enter theslot, the arm is then released to permit it to embrace the head, and theend closure is replaced, when the fuse will be ready for use. Vvlhen thefuse melts under an overload of current, the arm moves under itsinherent resiliency to in stantly draw the parts asunder, thuskeepingdown arcing, and moves the inner head, or its own free end, insuch relation to the trans'larent end closure as to clearly indicatethat the fuse has blown. Even while the fuse remains intactthe innerhead is within plain view through the window of the shell, and admits ofinspection as to its capacity. To renew a fused link it is merelynecessary to remove the shell from the socket, open up the end closure,clean out the fragments, and insert a new link in the manner alreadydescribed.

I claim:

l. A renewable link electric fuse, comprising a shell having at one endan opening through which to introduce the link, a link extending throughsaid opening and into the shell, and having one if its ends seated latsaid opening, and a resilient arm Within the shell; said arm beingconstructed With a seat for the inner end of the link, and said innerend of the link being constructed to conform to said seat and to be heldin engagement therewith by the resiliency of the arm.

2. A renewable link electric fuse, comprisingI a shell having at one enda seat for the link, and Within it a resilient arm constructed toembrace the link, and a link having an integral head fashioned toconform to the embracing portion of the arm.

8. In a renewable link electric fuse, a shell having` a seat for one endof a fusible link,and having` within ita resilient arm constructed witha seat for the other end of the link; the seat on the arm being concavedto embrace a head on the link, and being slotted to admit the link whenthe arm is pressed past-the head.

il. As a new article of manufacture, a renewable link for electricfuses, having` at its ends heads by which it is engaged in a fuse.mounting said heads being relatively large and small to permit thesmaller head to pass and the larger head to arrest passage inintroducing the link longitudinally into its mounting; an arm in thefuse mounting,` constructed with a seat, said smaller head adapted to bereceived by and to conform 'to the seat on said arm.

The fore, j;oing` speciication signed at Brooklyn, N. Y., this 5th dayof November, 1917.

JHN A. THAKE. in presence of.-

lTLonnNcn l. Cinxn'rnns, Pmnv'i'icn il. Coon.

